fix(FN-2897): harden npm bundle packaging and merge recovery flows

- Strip private @fusion/* workspace devDependencies from the published CLI manifest via prepare-publish-manifest and package metadata updates
- Replace cross-spawn usage and add staged bundle layout assertions to verify resolver output in dist packaging
- Add per-task/project model override resolution across core, dashboard settings/task modals, and route coverage with new regression tests
- Strengthen engine merge/recovery handling for paused/interrupted/squash paths and surface merger timeline activity with additional self-healing and merger tests
- Add changesets for npm bundle dependency fixes, project model override stabilization, and FTS5 corruption recovery

Fusion-Task-Id: FN-2897

packages/pi-claude-cli/src/process-manager.ts

@@ -6,12 +6,10 @@
  * Also provides startup validation for CLI presence and authentication.
  */
 
-import spawn from "cross-spawn";
-import { execSync } from "node:child_process";
+import { spawn, execSync, type ChildProcess } from "node:child_process";
 import { writeFileSync, unlinkSync } from "node:fs";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
-import type { ChildProcess } from "node:child_process";
 
 /**
  * Spawn a Claude CLI subprocess with all required flags for stream-json communication.